Question: Khan.scratchpad.disable(); For every level Ashley completes in her favorite game, she earns $420$ points. Ashley already has $420$ points in the game and wants to end up with at least $3990$ points before she goes to bed. What is the minimum number of complete levels that Ashley needs to complete to reach her goal?
Answer: To solve this, let's set up an expression to show how many points Ashley will have after each level. Number of points $=$ $ $ Levels completed $\times$ Points per level $+$ Starting points Since Ashley wants to have at least $3990$ points before going to bed, we can set up an inequality. Number of points $\geq 3990$ Levels completed $\times$ Points per level $+$ Starting points $\geq 3990$ We are solving for the number of levels to be completed, so let the number of levels be represented by the variable $x$ We can now plug in: $x \cdot 420 + 420 \geq 3990$ $ x \cdot 420 \geq 3990 - 420 $ $ x \cdot 420 \geq 3570 $ $x \geq \dfrac{3570}{420} \approx 8.50$ Since Ashley won't get points unless she completes the entire level, we round $8.50$ up to $9$ Ashley must complete at least 9 levels.